1. Field of the Invention
Exemplary embodiments of the present invention relate to a method and apparatus for detecting a received signal; and, more particularly, to a method and apparatus for detecting a received signal in a wireless communication system.
2. Description of Related Art
In the spectrum sensing of a wireless communication system, a signal received by a sensing receiver is detected as follows. First, the spectrum components of the entire bands of the received signal are calculated. Then, the calculated spectrum components are used to determine whether the received signal exists or not. In this case, a fast Fourier transform (FFT) algorithm for calculating the entire frequency bands at one time is mainly used to calculate the spectrum components.
In the method for detecting a received signal using the FFT algorithm, the entire frequency bands of the received signal are calculated at one time, as described above. Therefore, the complexity of calculation is high. Furthermore, when the received signal is an Advanced Television Systems Committee (ATSC) signal or a National Television Systems Committee (NTSC) signal, unnecessary frequency components should be calculated together, even though a signal having a relatively strong intensity exists in a specific frequency band. Therefore, the amount of calculation inevitably increases.
Meanwhile, a general wired communication system detects a received signal through a tone detection technique using the Goertzel algorithm. The Goertzel algorithm is an algorithm considering a wired channel environment in which a frequency offset does not exist, that is, the frequency is not distorted while a wireless signal is transmitted through a channel. Therefore, when the Goertzel algorithm is applied to a wireless communication system, that is, a wireless channel environment, it is impossible to detect a wireless signal in which a frequency offset exists.